much     of  Europe.     Monasteries     brewed  it  for
themselves  and for nearby  settlements.    By  the
9th  century,    alehouses   had     become  common
in   England,    with    individual  keepers     brewing
their   own.    Until   1200,   the English government
considered  ale to  be  a   food,   and did not tax it.
It  was in  medieval    Germany that    two great
innovations made    beer    largely what    it  is
today:  brewers preserved   and flavored    it  with
hops,   and began   to  ferment it  slowly  in  the
cold    to  make    mild-flavored   lager.
Hops     The     earliest    brewers     probably    added
herbs   and spices  to  beer,   both    to  give    it  flavor
and  to  delay   the     development     of  off-flavors
from     oxidation   and     the     growth  of  spoilage
microbes.   In  early   Europe  this    mixture,    called
gruit    in  German,     included    bog-myrtle,
rosemary,   yarrow, and other   herbs.  Coriander
was also    sometimes   used,   juniper in  Norway,
and  sweet   gale    (Myrica     gale)   especially  in
Denmark and Scandinavia.    It  was around  900
